Field of the Invention
The present invention relates to an ophthalmological apparatus that optically inspects a subject's eye.
Description of the Related Art
The ophthalmological apparatus includes an ophthalmological imaging device for acquiring an image of a subject's eye, and an ophthalmological measuring device for measuring characteristics of the subject's eye.
Examples of the ophthalmological imaging device are as follows: an optical coherence tomograph that acquires a tomographic image by using optical coherence tomography (OCT); a fundus camera for photographing a fundus; a scanning laser ophthalmoscope (SLO) that acquires an image of a fundus by using laser scanning with a confocal optical system; a slit lamp that acquires an image by using slit light to cut off an optical section of a cornea; and the like.
In addition, examples of the ophthalmological measuring device are as follows: an inspection device for refraction of eye (a refraction meter, or a keratometer) that measures refraction characteristics of a subject's eye; a tonometer; a specular microscope that acquires characteristics of a cornea (such as cornea thickness, and cell distribution); a wavefront analyzer that acquires aberration information on a subject's eye by using a Hartmann-Shack sensor; and the like.
In an ophthalmological inspection using these devices above, from a viewpoint of accuracy and correctness of an inspection, positioning of an optical system for inspection (device optical system) and a subject's eye is very important. This positioning is called alignment. The alignment includes operation of aligning an optical axis of the optical system for inspection with an axis of the subject's eye (xy-alignment), and operation of adjusting a distance between the subject's eye and the optical system for inspection (z-alignment).
There is known a conventional ophthalmological apparatus including an alignment optical system that projects an alignment index (such as luminous point alignment) for positioning of an optical system for inspection with respect to a subject's eye on the subject's eye (refer to Japanese Patent Laid-Open No. 2010-181172, for example). In this ophthalmological apparatus, while an observation image of a subject's eye, displayed in a monitor, is observed, positioning of optical system for inspection with respect to a subject's eye is performed by operating a control lever to three-dimensionally move the optical system for inspection so that two alignment index images enter within an alignment reference position mark (an alignment scale).